Non-convertible Preferred Stocks

1. It is hardly worthwhile to talk about nonconvertible preferred stocks, since their special tax status makes the safe ones much more desirable holdings by corporations – e.g., insurance companies – than by individuals.
2. The poorer-quality ones almost always fluctuate over a wide range, percentage wise, not too differently from common stocks. We can offer no other useful remark about them.

Ref: Intelligent Investor by Benjamin Graham